JP2006284038A - Combustion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise without substantially changing a constitution of a burner. <P>SOLUTION: In this combustion device, a burner port 22 is finely divided, and a band-shaped burner port dividing plate 26 having saw-tooth cut portions 25 on its upstream-side end portion is mounted. Thus the small eddy of flow is formed by the cut portions 25, and the transition of eddy with large disorder to the downstream of the burner portion 22 can be effectively prevented, and the noise can be substantially reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a combustion apparatus which is particularly aimed at reducing noise in a household or commercial combustion apparatus.

  A conventional combustion apparatus of this type is generally as shown in Patent Document 1.

  FIG. 4 is a view showing a conventional combustion apparatus described in Patent Document 1. In FIG. As shown in FIG. 4, a light burner unit 12 having a light flame outlet 11 at the top and a dark burner unit 14 having a light flame mouth 13 at the top are alternately provided. The pale flame mouth 11 and the dense flame mouth 13 are subdivided by the pale flame mouth dividing plate 15 and the rich flame mouth dividing plate 16.

  In the above configuration, fuel and air flow from the light inlet (not shown) of the light burner unit 12 and are mixed in the light burner unit 12 to generate a light air-fuel mixture that is rich in air. The air-fuel mixture flows out and forms a light flame. On the other hand, fuel and air flow from the rich inlet (not shown) of the rich burner unit 14 and are mixed in the rich burner unit 14 to produce a rich mixture with less air, and the rich mixture flows out of the rich flame port 13. , Form a deep flame. A light flame with a low flame temperature and a low NOx generation amount and a poor flammability is stabilized by a concentrated flame having a high flame temperature and a large amount of NOx generation, and can suppress the NOx generation amount as a whole. This burner is generally called a light and dark burner. The light mixture and the rich mixture are rectified by the pale flame mouth dividing plate 15 and the rich flame mouth dividing plate 16 and ejected from the pale flame mouth 11 and the rich flame mouth 13 to suppress noise.

By the way, an owl is known as a bird that flies very quietly, but there is a small “thorn” on the front edge of the wing. Some propeller fans have a serrated notch (often referred to as serration) at the blade trailing edge to reduce noise. These are thought to be because a fine vortex is formed at a sawtooth-shaped cut portion, and the development of a large vortex is effectively suppressed, and noise can be reduced.
Japanese Patent No. 2839049

  The air-fuel mixture immediately after jetting from the flame opening has a small flow disturbance, but the disturbance increases as the distance from the flame opening increases. In particular, a light air mixture with a large amount of air and a high flow rate tends to cause turbulence downstream of the flame opening, causing combustion noise.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a combustion apparatus that realizes further low noise.

  In order to solve the above-mentioned conventional problems, the flame opening is subdivided and provided with a strip-shaped flame opening dividing plate having a serrated notch at the upstream end.

  Thereby, it is possible to effectively suppress a vortex with a small flow formed by the cut portion and a transition to a large turbulence downstream of the flame opening.

  The combustion apparatus of the present invention can achieve a significant reduction in noise without greatly changing the configuration of the burner.

  1st invention is equipped with the burner formation board which forms a flame mouth, and the strip | belt-shaped flame mouth division board which has a serrated cut | notch part in an upstream edge part while subdividing the said flame mouth.

  Then, a vortex with a small flow is formed by the cut portion, and it is possible to effectively suppress the transition to a large-scale vortex accompanied by a large turbulence downstream of the flame opening, and the flame can be stabilized and combustion noise can be suppressed.

  The second invention includes a burner forming plate that forms a flame mouth, and a belt-like flame mouth dividing plate that subdivides the flame mouth and has a serrated notch at the downstream end.

  Then, by forming a notch at the downstream end of the flame port dividing plate, it is possible to more effectively suppress the transition to a large-scale vortex accompanied by a large turbulence downstream of the flame port, further suppressing combustion noise. it can.

  In a third aspect of the invention, in particular, in any one of the first and second aspects of the present invention, the rich burner that forms the rich flame port that burns the rich mixture and the pale burner that forms the pale flame port that burns the light mixture are alternately arranged. The pale flame mouth is subdivided by a strip-like flame mouth dividing plate having a sawtooth cut portion at the upstream or downstream end.

  And low NOx is realizable by making a combustion apparatus into a light and dark combustion system. Moreover, it is possible to stabilize a light flame that is fast and turbulent, and to suppress combustion noise.

  According to a fourth aspect of the invention, in particular, in the third aspect of the invention, the rich flame port is subdivided by a strip-shaped flame port dividing plate having a sawtooth-shaped cut portion at an upstream or downstream end.

  And a rich flame can also be stabilized and a combustion noise can further be suppressed.

  In a fifth aspect of the invention, in particular, in any one of the first to fourth aspects of the invention, the pitch of the cut portions is 1 mm or more and 5 mm or less.

  And by optimizing the notch size, it is possible to more effectively suppress the transition to a large-scale vortex accompanied by a large turbulence downstream of the flame opening, and further suppress the combustion noise. Moreover, it can be cut without difficulty.

  In a sixth aspect of the present invention, in particular, in any one of the first to fifth aspects, the depth of the cut portion is 1 mm or more and 10 mm or less.

  And by optimizing the notch size, it is possible to more effectively suppress the transition to a large-scale vortex accompanied by a large turbulence downstream of the flame opening, and further suppress the combustion noise. Also, the increase in weight can be minimized.

  In the seventh aspect of the invention, in particular, in any one of the third to sixth aspects of the invention, the fuel supply amount to the pale flame opening is set to be larger than the fuel supply amount to the rich flame opening.

  And the ratio of a light flame with few NOx can be increased, and low NOx is realizable as the whole combustion apparatus.

  In an eighth aspect of the invention, in particular, in any one of the third to seventh aspects of the invention, the opening area of the fuel / air inlet of the pale flame outlet is set larger than that of the fuel / air inlet of the rich flame outlet.

  A large amount of combustion air is supplied to the light flame outlet without receiving a large pressure loss, and a large amount of light air-fuel mixture can be generated to form a low NOx light flame. Moreover, the load of the fan that supplies the combustion air is reduced, and noise can be suppressed.

  In the ninth aspect of the invention, in particular, in any one of the third to eighth aspects of the invention, the area of the flame mouth of the pale flame mouth is set larger than the area of the flame mouth of the rich flame mouth.

  Then, the jet speed of the light mixture is not extremely increased, a stable light flame is formed, the load of the fan supplying the combustion air is reduced, and noise can be suppressed.

  According to a tenth aspect of the invention, in particular, in any one of the third to ninth aspects, the length of the mixing passage from the fuel / air inlet to the pale flame inlet to the pale flame inlet is set to It is set longer than the mixing passage to the rich flame outlet.

  And since a large amount of air and most of the fuel supplied from the fresh fuel / air inlet are sufficiently mixed while passing through a long passage, they are rectified and the turbulence is attenuated and supplied to the pale flame outlet. Super NOx combustion and reduction of combustion noise can be realized.

  In an eleventh aspect of the invention, in particular, in any one of the third to tenth aspects of the invention, the fuel / air inlet of the pale flame outlet is positioned below the fuel / air inlet of the rich flame outlet.

  And since the combustion air supplied by the fan is led from the fresh fuel / air inlet located upstream without receiving a large pressure loss to the pale flame outlet, the load on the fan is reduced and noise can be suppressed. it can.

(Embodiment 1)
1 (a) and 1 (b) are a plan view and a front view showing a combustion apparatus according to Embodiment 1 of the present invention.

  1 (a) and 1 (b), a pair of burner forming plates 21 face each other to form a flame port 22, a fuel / air inlet port 23, and a mixing passage 24. A flame-shaped flame dividing plate 26 having a serrated notch 25 at the upstream end is disposed at the top while the flame port 22 is subdivided. A suitable value is selected such that the pitch P of the cut portions 25 is 1 mm or more and 5 mm or less (for example, 3 mm), and the depth H of the cut portions 25 is 1 mm or more and 10 mm or less (for example, 2 mm).

  Next, the operation and action will be described. Fuel supplied from a fuel nozzle (not shown) and primary air supplied from a fan (not shown) flow in from the fuel / air inlet and mix in the mixing passage 24. It becomes a combustible air-fuel mixture. Although a turbulence accompanied by a large vortex occurs at the bent portion of the mixing passage 24, the large turbulence attenuates when the air-fuel mixture flows through a thin gap in the flame port dividing plate 26. Further, when the air-fuel mixture flows through the cut portion 25 of the flame port dividing plate 26, a small vortex is newly formed. The air-fuel mixture ejected from the flame port 22 is ignited by an ignition means (not shown) to form a flame. The small vortex formed by the cut portion 25 effectively suppresses the transition to a large vortex downstream of the flame mouth, thereby forming a stable flame. Complete combustion is performed by secondary air supplied by a fan (not shown) from both outer sides of the flame port 22.

  As described above, the burner forming plate that forms the flame opening, and the belt-shaped flame mouth dividing plate that subdivides the flame opening and has a serrated notch at the upstream end. Then, a vortex with a small flow is formed by the cut portion, and it is possible to effectively suppress the transition to a large-scale vortex accompanied by a large turbulence downstream of the flame opening, and the flame can be stabilized and combustion noise can be suppressed.

  Moreover, although the effect with respect to the noise reduction of a notch part can be exhibited, so that a pitch is small, if it is less than 1 mm, it will become difficult to press work. On the other hand, if it exceeds 5 mm, the effect of the incised portion is drastically reduced. Therefore, the pitch of the cut portion is set to 1 mm or more and 5 mm or less.

  Further, when the depth of the cut portion is less than 1 mm, the effect of the cut portion is almost lost. On the other hand, if it exceeds 10 mm, the effect is saturated. Also, it becomes heavier in terms of weight. The depth of the cut portion is 1 mm or more and 10 mm or less.

(Embodiment 2)
2 (a) and 2 (b) are a plan view and a front view showing a combustion apparatus according to Embodiment 2 of the present invention.

  2A and 2B, the present embodiment is different from the first embodiment in that a cut portion 25A is provided at the downstream end of the flame port dividing plate 26. Note that components having the same reference numerals as those in the first embodiment have the same configuration, and description thereof is omitted.

  The air-fuel mixture that has flowed between the flamelet dividing plates is separated when leaving the flamelet dividing plate, and a reverse flow is generated in the wake and transitions to a large vortex. Therefore, by forming a notch at the downstream end of the flame port dividing plate, it is more effective to make a transition to a large-scale vortex with a large turbulence downstream of the flame port than to provide a notch at the upstream end. Therefore, combustion noise can be further suppressed.

(Embodiment 3)
3 (a) and 3 (b) are a plan view and a front view showing the combustion apparatus according to Embodiment 3 of the present invention.

  3 (a) and 3 (b), a pair of light burner forming plates 31 face each other to form a light flame port 22, a light fuel / air introduction port 23, and a light mixing passage 24. The flare port 22 is subdivided, and a strip-shaped flare port dividing plate 36 having a sawtooth cut portion 35 at the upstream end is disposed at the top. These constitute the light burner 37. On the other hand, a pair of rich burner forming plates 38 are opposed to each other to form a rich flame port 39, a rich fuel / air introduction port 40, and a rich mixing passage 41. A strip-shaped thick flame port dividing plate 43 having a serrated cut portion 42 at the upstream end portion is arranged at the upper portion while the rich flame port 39 is subdivided. These constitute the dark burner 44. The light burners 37 and the dark burners 44 are alternately arranged so that the light flame mouth 32 and the rich flame mouth 39 are close to each other, and both ends in the arrangement direction become the rich flame mouths. Here, the opening area of the light fuel / air inlet 33 is set larger than that of the concentrated fuel / air inlet 40. Further, the area of the flame outlet 32 is set to be larger than the area of the flame outlet 39. Further, the length of the light mixing passage 34 from the light fuel / air introduction port 33 to the light flame port 32 is set longer than that of the rich mixing passage 41. Further, the light fuel / air inlet 33 is positioned below the rich fuel / air inlet 40.

  Next, the operation and action will be described. The light fuel supplied by the light fuel nozzle (not shown) and a large amount of light air supplied by the fan (not shown) flow in from the light fuel / air inlet 33. Then, it is mixed in the light mixing passage 34 to become a thin light mixture having an excess air ratio of about 1.8. A small vortex is formed in the light mixture by the cut portion 35 of the light flame dividing plate 36. When flowing between the light flame outlet dividing plates 36, the large vortex generated at the bent portion of the light mixing passage 34 is attenuated and rectified. The small vortex formed by the cut portion 25 can effectively suppress the transition to a large vortex downstream of the flame mouth. On the other hand, a rich fuel supplied by a rich fuel nozzle (not shown) and a small amount of rich air supplied by a fan (not shown) flow from the fresh fuel / air inlet 33 and enter the rich mixing passage 41. As a result, the mixture becomes a rich mixture with an excess air ratio of about 0.5. A small vortex is formed in the rich air-fuel mixture by the cut portion 42 of the rich flame mouth dividing plate 43. When flowing between the concentrated flame outlet dividing plates 43, a large vortex generated at the bent portion of the concentrated mixing passage 41 is attenuated and rectified. The small vortex formed by the cut portion 42 effectively suppresses a transition to a large vortex downstream of the flame mouth.

  The rich gas mixture ejected from the rich flame port 39 is ignited by an ignition means (not shown) to form a rich flame. The rich flame is ignited by a light air mixture ejected from the light flame port 32. The fuel supply amount to the pale flame port 32 is set to, for example, about 70% of the total supply amount and larger than the fuel supply amount to the rich flame port 39. As a result, even if the ratio of the light flame with low NOx is large, the flame temperature is high and the NOx generation amount is stabilized by a stable concentrated flame with a large amount of NOx, and the NOx generation amount can be suppressed as a whole.

  The air-fuel mixture has a large amount of air and the jet velocity from the flame outlet is faster than that of the rich gas mixture, but the notch 35 and 42 suppresses the turbulence of the wake behind the flame mouth, forms a stable flame, and reduces combustion noise. Can be suppressed.

Here, the opening area of the fresh fuel / air inlet 33 is set larger than the opening area of the concentrated fuel / air inlet 40. As a result, the combustion air supplied by the fan is supplied in a large amount to the light flame port 32 without receiving a large pressure loss, and a large amount of light mixture can be generated to form a low NOx light flame. Further, the load on the fan is reduced, and noise can be suppressed.
Further, the area of the flame outlet 32 is set to be larger than the area of the flame outlet 39. For this reason, the jet speed of the light mixture does not become extremely high, a stable light flame is formed, the load on the fan is reduced, and noise can be further suppressed.

  Further, the light mixing passage 34 from the light fuel / air introduction port 33 to the light flame port 32 is set longer than the dark. As a result, a large amount of air and a large amount of fuel are sufficiently mixed while passing through the passage, and are supplied to the light flame port 32. Therefore, a uniform light flame is formed, the amount of NOx generated is further reduced, and combustion noise can be further suppressed.

  Further, the light fuel / air inlet 33 is positioned below the rich fuel / air inlet 40. As a result, the combustion air supplied by the fan is guided from the fresh fuel / air inlet 33 located on the upstream side to the pale flame port 32 without receiving a large pressure loss, thereby reducing the fan load and suppressing noise. Can do.

  In addition, in each embodiment, although the structure which provides a notch part in a flame mouth dividing plate was demonstrated, it is still more preferable to provide a notch in the downstream end part of a burner formation board, ie, a flame mouth side.

  In each embodiment, the fuel has been described as a gas fuel such as city gas. However, a liquid fuel such as kerosene may be used after being gasified.

  As described above, the combustion apparatus according to the present invention uses gas fuel such as city gas or liquid fuel such as gasified kerosene, and can be burned with low noise while being simple and lightweight. Therefore, it can be widely applied as a combustion apparatus for hot water supply and heating.

(A) The top view which shows the combustion apparatus of Embodiment 1 of this invention (b) The front view which shows the combustion apparatus (A) Plan view showing the combustion apparatus of Embodiment 2 of the present invention (b) Front view showing the combustion apparatus (A) Plan view showing a combustion apparatus according to Embodiment 3 of the present invention (b) Front view showing the combustion apparatus Whole sectional view showing a conventional combustion device

Explanation of symbols

21 Burner forming plate 22 Flame port 25, 25A Cut portion 26 Flame port dividing plate 32 Pale flame port 33 Pale fuel / air introduction port 34 Pale mixing passage 35 Cut portion 36 Pale flame port dividing plate 37 Pale burner 39 Rich flame port 40 Dense Fuel / air inlet 41 Concentrated mixing passage 42 Cut section 43 Concentrated flame dividing plate 44 Concentrated burner

Claims (11)

A combustion apparatus comprising: a burner forming plate that forms a flame mouth; and a belt-like flame mouth dividing plate that subdivides the flame mouth and has a sawtooth-shaped cut portion at an upstream end. A combustion apparatus comprising: a burner forming plate that forms a flame opening; and a strip-shaped flame mouth dividing plate that subdivides the flame opening and has a serrated notch at the downstream end. A rich burner that forms a rich flame port that burns a rich mixture and a light burner that forms a pale flame port that burns a light mixture are alternately arranged, and the pale flame port is serrated at the upstream or downstream end. The combustion apparatus according to any one of claims 1 to 2, wherein the combustion apparatus is subdivided by a strip-shaped flame-portion dividing plate having a cut portion. The combustion apparatus according to claim 3, wherein the rich flame port is subdivided by a strip-shaped flame port dividing plate having a sawtooth-shaped cut portion at an upstream or downstream end portion. The combustion apparatus according to any one of claims 1 to 4, wherein a pitch of the cut portions is 1 mm or more and 5 mm or less. The combustion apparatus according to any one of claims 1 to 5, wherein the depth of the cut portion is 1 mm or more and 10 mm or less. The combustion apparatus according to any one of claims 3 to 6, wherein a fuel supply amount to the pale flame opening is set to be larger than a fuel supply amount to the rich flame opening. The combustion apparatus according to any one of claims 3 to 7, wherein an opening area of the fuel / air introduction port of the pale flame port is set larger than that of the fuel / air introduction port of the rich flame port. The combustion apparatus according to any one of claims 3 to 8, wherein a flame mouth area of the pale flame mouth is set larger than a flame mouth area of the rich flame mouth. The length of the mixing passage from the fuel / air inlet to the pale flame outlet at the pale flame outlet is set to be longer than that of the mixing passage from the fuel / air inlet to the rich flame outlet at the rich flame mouth. A combustion apparatus according to claim 1. The combustion apparatus according to any one of claims 3 to 10, wherein the fuel / air inlet of the pale flame outlet is positioned below the fuel / air inlet of the rich flame outlet.

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